If you think you may be pregnant, it is very important to see your health care provider. Remember to keep track of your menstrual periods and check in with your health care provider if your bleeding pattern changes. Are there any risks? Touching, pressing, or massaging your genitals with your fingers, or with an object such as a sex toy, can be sexually satisfying and can lead to orgasm. This flow, which comes out as blood, is your menstrual period. Periods are often irregular the first years. Your period may last 1 day or it may last 6 or 7. When you reach puberty and you are becoming a woman, your ovaries make hormones especially estrogen that cause breast development and menstrual periods. Key Facts Periods usually start between years of age.